A Linux operating system is divided into two parts. One part is core software, which is also referred to as kernel space, and the other part is a common application program, which is also referred to as user space. In the prior art, the Linux system has only one protocol stack instance, which runs in the kernel space. A single-instance protocol stack cannot implement parallel protocol processing on data, and has relatively low processing efficiency. Meanwhile, when a developer develops an application, the developer needs to develop the application in user mode. Therefore, when a user-mode application needs to access kernel-mode memory space, data in the memory space needs to be copied to the user space, and then the user-mode application can access the corresponding data. This results in relatively large resource consumption.